There are several known methods for manufacturing coated strings, some of which are described below (all of the mentioned patent literature is incorporated by reference herein). U.S. Pat. No. 4,539,228 (Lazarus) describes a method of treating metal musical instrument strings including wound strings to reduce break-in period and extend useful lifetime. The method includes cleaning the strings to remove abrasive particles, and filling microscopic pores, cavities and crevices of the strings and the interstices of wound strings with dry lubricant particles. The wound strings are soaked in a liquid Teflon®, polytetrafluoroethylene in a liquid carrier, for days to get the Teflon® between the wrap wire and the core wire.
U.S. Pat. No. 5,883,319 (Hebestreit et al.) describes a musical instrument string including a polymer cover that protects the string from contamination while also making the string easier to play. The cover comprises at least one layer of expanded polytetrafluoroethylene (ePTFE) that is sealed with a polymer coating.
U.S. Pat. No. 6,765,136 (Van Pamel) describes a method wherein a hydrophobic polymer is adhesively coated on the surfaces of a wound string within its interstitial voids, while the exterior surfaces remain uncoated. The polymer is applied by soaking the string in a liquid polymeric solution to flow the solution into the interstitial voids. The string is removed from the bath and the residual solution is removed from the exterior surface of the string using a resilient scraper. The string is hung to dry for 8 hours in a clean room environment at ambient temperatures and, more preferably, maintained at a temperature of between 20° C. and 25° C. Alternatively, the string is treated by a combination of heat and drying.
U.S. Pat. Appln. Publ. No. 2004/0255751 (Schlesinger) describes a method for coating musical instrument strings by treating the strings with a polymer vapor. The treatment may be applied to the core of the strings, to strands wrapped around the core, or both. The treatment may be applied either before or after wrapping the strands around the core.
Stringed musical instruments are often played in dark environments thereby requiring the players to either feel the strings in order to ensure that their fingers are correctly placed thereon or move to a lighted area to see the strings more clearly.
As such, it has been considered to include luminescent materials in musical instrument strings. For example, U.S. Pat. Appln. Publ. No. 2003/1096538 (Katchanov et al.) describes musical instrument strings for guitars and the like having longitudinal wrappings and/or surface contours to provide improved tactile response without adversely affecting the string tonal quality or producing undesirable noise. The musical instrument strings may have cores of metal wire, or may be composed of a synthetic material having a longitudinally contoured exterior surface and optionally a core impregnated with either a non-random dispersion of additive particles. Further, the strings 100 may be made of synthetic finer (plastic) that include additive particles as shown in FIGS. 7A-7C, wherein the additive particles may be a coloring agent or luminescent materials such as those that glow in the dark.
Instead of incorporating luminescent material in the strings, it has been conceived to added a luminescent compound to a bow that interacts with strings, e.g., U.S. Pat. No. 6,280,654 (Digman et al.). Instead of adding the luminescent compound to the bow, U.S. Pat. No. 5,977,462 (Wolfson) describes a fret board having indicators that indicate the pitch produced when the string is pressed down, wherein the indicators may be colored, fluorescent and/or include any discernible characteristic that is discernible by sight.
There is always a need to improve the manner in which musical instrument strings are coated and the invention provides an improvement over the cited prior art.
Moreover, a new method for incorporating luminescent compounds into musical instrument strings is needed which provides better manufacturing capabilities than the prior art methods.